1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>ioctl VIDIOC_OVERLAY</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="LINUX MEDIA INFRASTRUCTURE API"><link rel="up" href="user-func.html" title="Appendix&#160;A.&#160;Function Reference"><link rel="prev" href="vidioc-log-status.html" title="ioctl VIDIOC_LOG_STATUS"><link rel="next" href="vidioc-prepare-buf.html" title="ioctl VIDIOC_PREPARE_BUF"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">ioctl VIDIOC_OVERLAY</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="vidioc-log-status.html">Prev</a>&#160;</td><th width="60%" align="center">Appendix&#160;A.&#160;Function Reference</th><td width="20%" align="right">&#160;<a accesskey="n" href="vidioc-prepare-buf.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="vidioc-overlay"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>VIDIOC_OVERLAY &#8212; Start or stop video overlay</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">ioctl</b>(</code></td><td>int <var class="pdparam">fd</var>, </td></tr><tr><td>&#160;</td><td>int <var class="pdparam">request</var>, </td></tr><tr><td>&#160;</td><td>const int *<var class="pdparam">argp</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1115528868"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>fd</code></em></span></dt><dd><p>File descriptor returned by <a class="link" href="func-open.html" title="V4L2 open()"><code class="function">open()</code></a>.</p></dd><dt><span class="term"><em class="parameter"><code>request</code></em></span></dt><dd><p>VIDIOC_OVERLAY</p></dd><dt><span class="term"><em class="parameter"><code>argp</code></em></span></dt><dd><p></p></dd></dl></div></div><div class="refsect1"><a name="idp1115532916"></a><h2>Description</h2><p>This ioctl is part of the <a class="link" href="overlay.html" title="Video Overlay Interface">video
2    overlay</a> I/O method. Applications call
3    <code class="constant">VIDIOC_OVERLAY</code> to start or stop the
4    overlay. It takes a pointer to an integer which must be set to
5    zero by the application to stop overlay, to one to start.</p><p>Drivers do not support <a class="link" href="vidioc-streamon.html" title="ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF"><code class="constant">VIDIOC_STREAMON</code></a> or
6<a class="link" href="vidioc-streamon.html" title="ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF"><code class="constant">VIDIOC_STREAMOFF</code></a> with <code class="constant">V4L2_BUF_TYPE_VIDEO_OVERLAY</code>.</p></div><div class="refsect1"><a name="idp1115588836"></a><h2>Return Value</h2><p>On success <span class="returnvalue">0</span> is returned, on error <span class="returnvalue">-1</span> and the <code class="varname">errno</code> variable is set appropriately. The generic error codes are described at the <a class="link" href="gen_errors.html#gen-errors" title="Table&#160;19.1.&#160;Generic error codes">Generic Error Codes</a> chapter.</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><span class="errorcode">EINVAL</span></span></dt><dd><p>The overlay parameters have not been set up. See <a class="xref" href="overlay.html" title="Video Overlay Interface">the section called &#8220;Video Overlay Interface&#8221;</a> for the necessary steps.</p></dd></dl></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="vidioc-log-status.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="user-func.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="vidioc-prepare-buf.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">ioctl VIDIOC_LOG_STATUS&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;ioctl VIDIOC_PREPARE_BUF</td></tr></table></div></body></html>
7